Streaming audio and video (A/V) transmissions have become commonplace due to computer networks which are able to carry the digital A/V data at a rate sufficient to provide a user with a real time audio or video output image. Streaming transmissions should occur at real-time or near real-time so that the user perceives an intelligible audio or video image. Such streaming transmissions occur in a series of frames, in which each frame contains symbols indicative of a particular audio or video signal. The symbols are output, or played back, to the user in sequence from the frame. Each frame, therefore, represents a predetermined time interval of playback. Lost or late frames, while not fatal to transmissions, are perceived as a “blip” or “pop” for the duration, or interval, of the frame. Accordingly, sufficient frames should be received in a particular timeframe in order to satisfy the aggregate interval they represent i.e. an average of one frame per time interval represented by that frame.
In a wireless network, the frames are transmitted via a radio frequency (RF) medium according to a particular protocol, such as IS—95 or others. However, wireless networks tend to exhibit different performance characteristics than their wired network counterparts. In particular, wireless networks have higher rates of lost or late packets due to interference and other factors which affect propagation of the RF signals. Accordingly, wireless networks typically employ a plurality of shared RF channels among multiple users, in which a plurality of wireless connections are shared over the same wireless channel. The channels are switched, or multiplexed, among the multiple wireless connections according to a predetermined protocol, such Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), or Frequency division multiple access (FDMA).
In the case of streaming A/V transmissions, such sharing occurs at a rate sufficient to provide transmission of the frames according to the time interval represented by the frame. While transmissions such as email can be transmitted over time, aggregated, and presented to a user after complete reception, streaming, real-time audio or video should be received according to the predetermined rate so that the output image perceived by the user is intelligible, and not prone to “blips” and “pops.”
It would be beneficial, therefore, to interleave symbols in one frame with symbols in an adjacent frame so that, in the case of lost or late packets, the duration of the interval during which no symbols are available for playback is reduced.